Electronic device, communication method and storage medium in wireless communication system

ABSTRACT

An electronic device on the user side comprising a processing circuitry configured to report to a network control device a first type of channel state information (CSI) by using a resource for the first type of channel state feedback allocated by the network control device; make a determination that a second type of channel state feedback is required; and notify the network control device of the determination.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a National Stage Application based onPCT/CN2018/085646, filed on 4 May 2018, and claims priority to ChinesePatent Application No. 201710427221.0, filed on 8 Jun. 2017, the entirecontents of which being incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to an electronic device, a communicationmethod and a storage medium in wireless communication system, and inparticular, to an electronic device, a communication method and astorage medium for channel state feedback/reporting in wirelesscommunication system.

BACKGROUND ART

With further development of wireless communication technologies,techniques for reporting channel state information (CSI) is playing anincreasingly important role. The channel state information reflectsproperties of a wireless channel and describes fading factors of asignal on a transmission path, such as signal scattering, environmentalfading, range fading and the like. The conventional channel statefeedback is typically based on PMI codebook, and can provide informationsuch as Channel Quality Indicator (CQI), Precoding Matrix Indicator(PMI), Rank Indicator (RI), Channel State Information Reference SignalResource Indicator (CSI-RS Resource Indicator, CRI) or the like. Basedon the acquired channel state information, it is possible to adapt thecommunication system to the current channel state, thereby guaranteeinghigh-reliability and high-rate communications, especially formulti-antenna communication system.

In addition, an enhanced channel state feedback is now being discussedat present. As compared with the convention channel state feedback, theenhanced channel state feedback is able to provide channel stateinformation with a higher spatial resolution (with a smallergranularity) and/or with a higher richness, and thus, it is possible toobtain accurate channel information even in case of acute channelscattering or angle scattering. However, the enhanced channel statefeedback requires more overhead on processing and transmission.

The inventors of the present disclosure have noticed there may be arequirement to choose an apprariate channel state feedback as needed.

For example, Multiple Input Multiple Output (MIMO) is a criticaltechnique for the physical layer in the 4G communication or even in the5G communication, and the industry has come up with various techniquesfor enhancing MIMO, in which multi-user MIMO (MU-MIMO) is a hot issue intheoretical research and standardization, and is lively discussed in thestandardization of the next generation NR MIMO. Among others, theaccuracy of the channel state information is most important to MU MIMO,especially in case of a large number of transmitting antennas. However,in a MU MIMO scenario such as downlink multi-user spatial multiplexing,communication resources used by the users are required to havesufficiently good spatial orthogonality therebetween.

As shown in FIG. 1, two users UE1 and UE2, which are closegeographically, perform data transmission with the base station throughthe MU MIMO. When the orthogonality between each of the users and thebase station is bad, the inter-channel interference is increased, and itis possible to cause a reduction of the accuracy of the channel stateinformation reported by the users and thus a reduction of performance ofthe MU MIMO. In this case, there is a need to use a more accuratechannel state feedback.

In addition to the scenario as described above, there may be other caseswhere the communication system is required to use another channel statefeedback different from the current one.

SUMMARY OF THE INVENTION

An object of the present application is to propose a technology forchanging the type of the channel state feedback so as to meet the needas described above.

A brief overview regarding the present disclosure is given hereinafter,for purpose of a basic understanding of some aspects of the presentdisclosure. However, it will be appreciated that the overview is not anexhaustive description of the present disclosure. It is not intended tospecify key portions or important portions of the present disclosure,nor to limit the scope of the present disclosure. It aims at describingsome concepts about the present disclosure in a simplified form andserves as a preorder of a more detailed description given later.

According to an aspect of the present disclosure, there provides anelectronic device on a side of user, comprising a processing circuitryconfigured to report to a network control device a first type of channelstate information by using a resource for the first type of channelstate feedback allocated by the network control device, make adetermination that a second type of channel state feedback is required,and notify the network control device of the determination.

According to an aspect of the present disclosure, there provides anelectronic device on a side of network control, comprising a processingcircuitry configured to allocate a resource for a first type of channelstate feedback to a user device, receive from the user device annotification regarding a determination that a second type of channelstate feedback is required, allocate a resource for the second type ofchannel state feedback to the user device; and receive the second typeof channel state information.

According to an aspect of the present disclosure, there provides anelectronic device on the side of network control, comprising aprocessing circuitry configured to allocate a resource for a first typeof channel state feedback to a user device, make a determination that asecond type of channel state feedback is required, and notify the userdevice of the determination.

According to an aspect of the present disclosure, there provides anelectronic device on the side of user, comprising a processing circuitryconfigured to report to a network control device a first type of channelstate information by using a resource for the first type of channelstate feedback allocated by the network control device, receive from thenetwork control device an notification regarding a determination that asecond type of channel state feedback is required, and report to thenetwork control device the second type of channel state information byusing a resource for the second type of channel state feedback allocatedby the network control device.

According to an aspect of the present disclosure, there provides acommunication method on the side of user, comprising reporting to anetwork control device a first type of channel state information byusing a resource for the first type of channel state feedback allocatedby the network control device, making a determination that a second typeof channel state feedback is required, and notifying the network controldevice of the determination.

According to an aspect of the present disclosure, there provides acommunication method on the side of network control, comprisingallocating a resource for a first type of channel state feedback to auser device, making a determination that a second type of channel statefeedback is required, and notifying the user device of thedetermination.

According to an aspect of the present disclosure, there provides acommunication method on the side of network control, comprisingallocating a resource for a first type of channel state feedback to auser device, receiving from the user device an notification regarding adetermination that a second type of channel state feedback is required,allocating a resource for the second type of channel state feedback tothe user device; and receiving the second type of channel stateinformation.

According to an aspect of the present disclosure, there provides acommunication method on the side of user, comprising reporting to anetwork control device a first type of channel state information byusing a resource for the first type of channel state feedback allocatedby the network control device, receiving from the network control devicean notification regarding a determination that a second type of channelstate feedback is required, and reporting to the network control devicethe second type of channel state information by using a resource for thesecond type of channel state feedback allocated by the network controldevice.

According to an aspect of the present disclosure, there provides Anon-transitory computer readable storage medium storing executableinstructions which, when executed, implements any of the communicationmethods as described above.

According to each of the aspects of the present disclosure, the wirelesscommunication system is able to employ appropriate channel statefeedback as needed, and thus can make an optimum compromise between theaccuracy of the channel state information and the overhead.

BRIEF DESCRIPTION OF THE DRAWINGS

A better understanding of the present disclosure can be achieved byreferring to the detailed description given hereinafter in connectionwith the accompanying figures, wherein same or similar reference signsare used to indicate same or similar components throughout the figures.The figures are included in the specification and form a part of thespecification along with the following detailed descriptions, forfurther illustrating embodiments of the present disclosure andexplaining the theory and advantages of the present disclosure. Wherein,

FIG. 1 illustrates a scenario where user devices, which are closegeographically, carry out MU MIMO;

FIG. 2A is a block diagram illustrating an electronic device on the sideof user according to a first embodiment of the present disclosure;

FIG. 2B is a signaling flowchart of a communication method performed bythe electronic device on the side of user according to the firstembodiment of the present disclosure;

FIG. 3A is a block diagram illustrating an electronic device on the sideof network control according to the first embodiment of the presentdisclosure;

FIG. 3B is a signaling flowchart of a communication method performed bythe electronic device on the side of network control according to thefirst embodiment of the present disclosure;

FIG. 4A illustrates an example of a determination process according tothe first embodiment of the present disclosure;

FIG. 4B illustrates another example of the determination processaccording to the first embodiment of the present disclosure;

FIG. 4C illustrates an example of a pre-determination process accordingto the first embodiment of the present disclosure;

FIG. 5 illustrates a communication procedure when the first embodimentof the present disclosure is applied to the MU MIMO scenario;

FIG. 6A is a block diagram illustrating an electronic device on the sideof network control according to a second embodiment of the presentdisclosure;

FIG. 6B is a signaling flowchart of a communication method performed bythe electronic device on the side of network control according to thesecond embodiment of the present disclosure;

FIG. 7A is a block diagram illustrating an electronic device on the sideof user according to a first embodiment of the present disclosure;

FIG. 7B is a signaling flowchart of a communication method performed bythe electronic device on the side of user according to the secondembodiment of the present disclosure;

FIG. 8A illustrates an example of the determination process according tothe second embodiment of the present disclosure;

FIG. 8B illustrates another example of the determination processaccording to the second embodiment of the present disclosure;

FIG. 8C illustrates an example of the pre-determination processaccording to the second embodiment of the present disclosure;

FIG. 9 illustrates a communication procedure when the second embodimentof the present disclosure is applied to the MU MIMO scenario;

FIG. 10 is a block diagram illustrating a first example of theelectronic device on the side of network control according toembodiments of the present disclosure;

FIG. 11 is a block diagram illustrating a second example of theelectronic device on the side of network control according toembodiments of the present disclosure;

FIG. 12 is a block diagram illustrating an example of schematicconfiguration of a smart phone according to embodiments of the presentdisclosure; and

FIG. 13 is a block diagram illustrating an example of schematicconfiguration of an automobile navigation device according toembodiments of the present disclosure.

Further features of the present invention will become apparent from thefollowing description of exemplary embodiments with reference to theattached drawings.

DESCRIPTION OF EMBODIMENTS

The illustrative embodiments of the invention will be describedhereinafter with reference to the drawings. For purpose of clarity andsimplicity, not all features are described in the specification. Notethat, however, many settings specific to the implementations can be madein implementing the invention according specific requirements, so as toachieve specific goals of the developers, for example, to comply withthe limiting conditions related to apparatus and service, which varyfrom one implementation to another. Furthermore, it will be appreciatedthat the developing work will be a routine task, despite complex andtedious, for those skilled in the art who benefit from the presentdisclosure.

In addition, note that the figures illustrate only steps of a processand/or components of a device that are closely related to the technicalsolutions of the invention, and omit other details that are in littlerelation to the invention.

Next, detailed descriptions will be given for the illustrativeembodiments and application examples according to the invention withreference the accompanying drawings.

The First Embodiment 1.1 The Electronic Device on the Side of User andIts Communication Method According to the First Embodiment

The electronic device 200 on the side of user and its communicationmethod according to the first embodiment will be described below withreference to FIGS. 2A and 2B.

FIG. 2A is a block diagram illustrating the electronic device 200according to the first embodiment. The electronic device 200 is a userdevice such as mobile phone, in-vehicle device, a tablet or the like orits element. As illustrated in FIG. 2A, the electronic device 200includes at least a processing circuitry 201. The processing circuitry201 of the electronic device 200 provides various functionalities of theelectronic device 200. For example, the processing circuitry 201 caninclude a reporting unit 202, a determining unit 203 and a notifyingunit 204.

The reporting unit 202 is configured to report channel state information(CSI) by using a resource for channel state feedback allocated by anetwork control device. As used herein, the network control device (forexample, the electronic device 300 as described below) is a base stationsuch as eNB in the 4G communication standard or gNB in the 5Gcommunication standard or a communication apparatus performing similarfunctionalities as the base station, but is not limited to this.Typically, to acquire information on channel state of a communicationchannel between the electronic device 200 and the network controldevice, the network control device allocates to the electronic device200 a resource for the channel state feedback, for example, referencesignals such as cell-specific reference signal (CRS) or CSI referencesignal (CSI-RS), pilot signals or the like, in order to perform channelevaluation. Hereinafter, CSI-RS is used frequently as example of the“resource for channel state feedback”, but those skilled in the art willappreciate that the present disclosure is not intended to limit this andany appropriate reference signals can be used. Depending on the specifictype of the channel feedback and the frequency of desirably acquiringthe CSI, the resource for channel state feedback may be aperiodic,semi-persistent or periodic. The reporting unit 202 of the electronicdevice 200 can acquire desired CSI by measuring the reference signalsuch as CSI-RS, and report the acquired CSI to the network controldevice.

The reporting unit 202 may perform the channel state feedback in manymanners. For example, the reporting unit 202 may perform the channelstate feedback in an implicit manner, that is, report to the networkcontrol device information characterizing the channel state, such asCQI, PMI, RI, CRI or the like. Alternatively, the reporting unit 202 canperform the channel state feedback in an explicit manner, that is,report channel parameters directly or compressed channel parameters tothe network control device.

The reporting unit 202 can perform the enhanced channel state feedbackin addition to the conventional one based on PMI-codebook. The enhancedchannel state feedback includes several categories: precoded feedbackbased on linearly combined codebook, feedback for channel covariancematrix and hybrid CSI feedback. These feedback categories can provideCSI with a higher resolution, a higher accuracy, and a richer content,and can be collectively referred to as the enhanced channel statefeedback.

Specifically, the precoded feedback based on linearly combined codebook,for example, may be a feedback based on a two-level codebook W=W1W2,wherein W1 represents a set of L orthogonal beams selected fromtwo-dimensional discrete Fourier transform (2D DFT) beams byoversampling basis vectors composed by the 2D DFT beams, in which thebeam selection is in a granularity of wideband. W2 represents a linearcombination of the L beams in W1, L is configurable and can be 2, 3, 4,6 or the like. With respect to linear combination coefficients of thebeams in W2, the granularity of phase quantization is subband, and thequantization granularity of magnitude scaling factors can be wideband orsubband. The feedback for channel covariance matrix is a feedback afterquantizing or compressing the channel variance matrix based on a set ofM orthogonal basis vectors, and what is reported can include the M basisvectors and respective coefficients, and the granularity of thereporting for variance matrix is wideband. The hybrid CSI feedback, forexample, can combine the codebook of the two channel state feedbackdescribed above and the channel state feedback of LTE (for example,LTE-Class-B-type-like CSI feedback).

The determining unit 203 of the electronic device 200 is configured tomake a determination that whether the type of channel state feedbackneeds to be changed. The determining unit 203 can perform suchdetermination process based on various factors, including requirements acommunication service has on the content or accuracy of the CSI, channelinterferences such as inter-user interference, overhead on theprocessing and transmission of the CSI, or the like. In the presentdisclosure, assuming that the current channel state feedback is of afirst type and is used to report the first type of CSI. The determiningunit 203 can determine a second type of channel state feedback is to beused to report the second type of CSI. The first type is different fromthe second type. The determining unit 203 further determines thespecific category of the second type of channel state feedback.

In one example, in response to having detected a channel interference orthe accuracy of the CSI required by the communication service gettinghigher, the determining unit 203 can make the following determination.CSI with a higher accuracy is to be reported, that is, the accuracy ofthe second type of channel state feedback is higher than the first typeof channel state feedback. In one example, in response to havingdetected a favorable channel state or the accuracy of CSI required bythe communication service being not high, the determining unit 203 canmake the following determination: CSI with a lower accuracy is to bereported, that is, the accuracy of the second type of channel statefeedback is lower than the first type of channel state feedback. In oneexample, based on requirements the communication has on the reportedcontent, the determining unit 203 can make a determination that achannel state feedback related to the reported content is to beperformed, that is, the second type of channel state feedback is toreport the reported content as needed, for example, CQI, PMI, RI, CRI,channel parameters or compressed channel parameters, channel covariancematrix, or the like. After the determining unit 203 has determined thespecific category of the second type of channel state feedback, thedetermination result is presented to the notifying unit 204 so as tonotify the network control device.

The notifying unit 204 is configured to notify the network controldevice (for example, the electronic device 300 as described below) ofthe determination result made by the determining unit 203. The notifyingunit 204 may perform the notifying by generating a message including thedetermination result and send it to the network control device. Forexample, the determination result can be included in uplink controlinformation (UCI) transmitted via physical uplink control channel(PUCCH) or physical uplink shared channel (PUSCH), or can be included ina starting portion of a CSI packet transmitted via the PUSCH.Alternatively, the determination result can be included in a newlydefined signaling and reported via the PUCCH or PUSCH. The informationon the determination result may indicate the specific category ofchannel state feedback which is desired to be made next, thereby thenetwork control device can learn which channel state feedback is to beperformed next upon receiving the notification issued by the notifyingunit 204, and allocates corresponding resources (e.g. CSI-RS) for thereporting unit 202 to perform the second type of channel state feedback.

The electronic device 200 can further include a communication unit 205and a memory 200.

The communication unit 205 of the electronic device 200 can beconfigured to communicate with the network control device under controlof the processing circuitry 201, to send the notification including thedetermination result, the CSI or the like to the network control device.The communication unit 205 can be implemented as a transmitter or atransceiver. In one example, the communication unit 205 can beimplemented as a communication interface component of an antenna device,a radio frequency circuit and the like. The communication unit 205 isdepicted with broken lines, since it may also reside within theprocessing circuitry 201 or outside the electronic device 200.

The memory 206 of the electronic device 200 can store variousinformation generated by the processing circuitry 201 (e.g. thedetermination result of the determining unit 203), program or data usedby the electronic device 200 to operate, data or information to betransmitted by the communication unit 205 (e.g. the CSI). The memory 205is depicted by broken lines, since it may also reside within theprocessing circuitry or outside the electronic device 200. The memory206 can be a volatile memory and/or a non-volatile memory. For example,the memory 206 may include but is not limited to a random access memory(RAM), a dynamic random access memory (DRAM), a static random accessmemory (SRAM), a read only memory (ROM), a flash memory.

FIG. 2B depicts a communication method performed by the electronicdevice 200 on the side of user.

As shown in FIG. 2B, in step S21, the reporting unit 202 can report to anetwork control device the first type of CSI by using a resource for thefirst type of channel state feedback allocated by the network controldevice. The type of the channel state feedback performed by reportingunit 202 is associated with the resource allocated by the networkcontrol device. For example, in an example, the network control devicecan allocate periodic CSI-RS resources to the electronic device 200,such that the reporting unit 202 can measure, for example, CQI,parameters related with channel matrix or the like based on the CSI-RSresources, and report these CSI to the network control deviceperiodically.

In step S22, the determining unit 203 of the electronic device 200determines whether the second type of channel state feedback is needed.The determination process can be performed based on various factors, andexamples of the determination process will be described in detail laterin the following Section 1.3. For purpose of illustration, assuming thatwhen severe channel interferences are detected, in order to ensure theaccuracy of the CSI, the determining unit 203 can determine that achannel state feedback which is different from the first type of channelstate feedback and has a higher accuracy is to be employed, for example,the determining unit 203 can make a determination that any of thefeedback based on linearly combined codebook, the feedback forcovariance matrix, and the hybrid channel state feedback. If thedetermining unit 203 determines that the type of the channel statefeedback need not to be changed, the reporting unit 202 will continue toperform the first type of channel state feedback.

In step S23, the notifying unit 204 of the electronic device 200notifies the network control device of the determination result made bythe determining unit 203. Such notifying process can be implemented bygenerating and transmitting a message including the specific category ofthe second type of channel state feedback. Specific examples of thenotifying process will be described in the following Section 1.4.Thereby, upon receiving the notification, the network control device isable to learn which channel state feedback is to be employed next and toallocate corresponding CSI-RS resources.

Optionally, as shown in the broken-line box, the communication methodperformed by the electronic device 200 can further include a step S24.In step S24, the reporting unit 202 of the electronic device 200 canreport the second type of CSI by using the resources (e.g. (CSI-RS) forthe second type of channel state feedback allocated by the networkcontrol device. Note that at the moment, the reporting unit 202 may stopthe first type of channel state feedback and perform only the secondtype of channel state feedback, or may perform the first type of channelstate feedback and the second type of channel state feedbacksimultaneously.

1.2 The Electronic Device on the Side of Network Control and ItsCommunication Method According to the First Embodiment

The electronic device 300 on the side of network control and itscommunication method according to the first embodiment will be describedbelow with reference to FIGS. 3A and 3B.

FIG. 3A is a block diagram illustrating the electronic device 300according to the first embodiment. The electronic device 300 is a basestation such as eNB in the 4G communication standard or gNB in the 5Gcommunication standard, or a communication means performing similarfunctionalities. The electronic device 300 includes at least aprocessing circuitry 301. The processing circuitry 301 provides variousfunctionalities of the electronic device 300. For example, theprocessing circuitry 301 can include an allocating unit 302, anotification receiving unit 303 and a CSI receiving unit 304.

The allocating unit 302 of the electronic 300 is configured to allocatea resource for channel state feedback to a user device (e.g. theelectronic device 200) depending to the type of the channel statefeedback. The resource for channel state feedback can be variousdownlink reference signals or pilot signals, such as CRS, CSI-RS or thelike. The allocating unit 302 can allocate reference signals fordifferent types of channel state feedback as needed. The referencesignals such as CSI-RS or the like is associated with particular timeand frequency resources, for purpose of a channel evaluation under theseparticular time and frequency resources. In one example, the allocatingunit 302 can allocate CSI-RS resources periodically, for the user deviceto measure conventional CSI such as CQI, PMI, RI and the like. However,if the notification receiving unit 303 as described below receives anotification that another type of channel state feedback needs to beperformed, the allocating unit 302 can allocate CSI-RS resources for thechannel state feedback which is of the category indicated in thisnotification.

The notification receiving 303 of the electronic device 300 isconfigured to receive the notification regarding whether there is a needto perform another type of channel state feedback different from thecurrent type of channel state feedback. This notification can beincluded in an UCI signaling message or a newly defined signalingmessage, and indicates the specific category of the another type ofchannel state feedback.

After receiving the notification, the electronic device 300 can learnthe category of the channel state feedback to be performed next, andthus allocate corresponding resources for the channel state feedback tothe user device, such as CSI-RS resources.

The CSI receiving unit 304 is configured to receive CSI from the userdevice, and depending on the specific category of the ongoing channelstate feedback, the CSI may include CQI, PMI, RI, CRI, channelparameters or compressed channel parameters, channel covariance matrix,or the like. The received CSI provides an estimate of the currentwireless transmission environment, and can provide a reference for theresource scheduling or precoding of the downlink transmission.

The electronic device 300 can further include a communication unit 305and a memory 306.

The communication unit 305 of the electronic device 300 can beconfigured to communicate with the user device under control of theprocessing circuitry 301. The communication unit 305 can be implementedas a transceiver. In one example, the communication unit 305 can beimplemented as a communication interface component of an antenna device,a radio frequency circuit, and the like. The communication unit 305 isdepicted with broken lines, since it can also reside within theprocessing circuitry 301 or outside the electronic device 300.

The memory 306 of the electronic device 300 can store variousinformation generated by the processing circuitry 301, program or dataused by the electronic device 300 to operate, data or information to betransmitted by the communication unit 305. The memory 306 is depicted bybroken lines, since it can also reside within the processing circuitry301 or outside the electronic device 300. The memory 306 can be volatilememory and/or non-volatile memory. For example, the memory 306 caninclude but is not limited to a random access memory (RAM), a dynamicrandom access memory (DRAM), a static random access memory (SRAM), aread only memory (ROM), a flash memory.

The communication method performed by the electronic device 300 will bedescribed below with reference to FIG. 3B.

As shown in FIG. 3B, in step S31, the allocating unit 302 of theelectronic device 300 allocates the resource of the first type ofchannel state feedback to the user device. For example, in one example,the network control device can allocate periodic CSI-RS resources to theuser device (e.g. the electronic device 200 as described above), for theuser device to periodically report the channel state information such asCQI, PMI, RI.

Then, in step S32, the notification receiving unit 303 of the electronicdevice 300 receives from the user device the notification regarding thedetermination that the second type of channel state channel needs to beperformed, wherein the second type is different from the first type.Such notification includes indicative information about the specificcategory of the second type of channel state feedback.

In step S33, depending on the indicative information, the electronicdevice 300 is able to determine which channel state report is to beperformed next, and allocate the resource for the second type of channelstate feedback, such as CSI-RS resource, to the user device by theallocating unit 301.

Next, in step S34, the CSI receiving unit 304 of the electronic device300 receives the second type of CSI reported by the user device, such asthe CSI based on linearly combined codebook, the channel covariancematrix, the hybrid CSI or the like, which has a higher accuracy.

When receiving the second type of CSI, the CSI receiving unit 304 canstop receiving the first type of CSI. Alternatively, the CSI receivingunit 304 can receive both the second type of CSI and the first type ofCSI.

1.3 The Determination Process According to the First Embodiment

As explained in the above section, in the first embodiment of thepresent disclosure, the determination process of determining whetherthere is a need to perform another channel state feedback of the typedifferent from that of the current channel state feedback is done at thedevice on the side of user (e.g. the electronic device 200). Thedetermination process is performed in consideration of various factors.For purpose of illustration, an example of such determination processimplemented in the multi-user communication scenario is described indetail below. As used herein, the multi-user communication for exampleis the MU MIMO communication.

In the MU MIMO communication, multiple user devices, which are closegeographically to each other, are brought into the communication systemby spatial multiplexing, and each user device is allocated with one ormore layers for data transmission. The layers used by individual userdevice are independent of each other, but depending on the orthogonalitybetween the layers used by respective user devices, there is inter-layerinterference to some extent. When the inter-layer interference issevere, the transmission performance of the MU MIMO communication isreduced, which may cause the accuracy of the CSI to decrease.

By evaluating such inter-layer interference, it can be determinedwhether the current channel state feedback meets the need or not.

1.3.1 Determination Process Based on Orthogonality Between CommunicationResources

When the communication is carried out with multiplexing andmultiple-access technology, the inter-user interference depends greatlyon the orthogonality between communication resources used by the userdevices. Generally speaking, the orthogonality between the communicationresources (e.g. layers in the spatial multiplexing) allocated torespective user devices is better, the inter-user interference issmaller, and on the contrary the inter-user interference is larger.Therefore, based on the orthogonality between the communicationresources used by the user devices, it can be determined whether toswitch to another type of channel state feedback.

In one example, the orthogonality can be decided based on demodulationreference signal (DMRS) ports corresponding to respective layers of eachuser device. In the case where a single user device may use a pluralityof layers, there are different DMRS ports corresponding to respectivelayers. The DMRS is an uplink reference signal introduced in Release 10for LTE, and is used for correlated demodulation of the uplink controlchannel and the uplink data channel. Scrambling code sequence of theDMRS is selected from a predefined set of scrambling code sequences bythe user device, and is identified by scrambling code sequence number.Since the scrambling code sequence can indicate corresponding DMRS port,the orthogonality between layers used by different user devices can bedecided by a correlation degree between the scrambling code sequences ofrespective DMRS ports.

FIG. 4A is flowchart of an example of the determination process based onDMRS configuration information.

First, as shown by the dotted arrow, the present user device (the userdevice performing the communication method according to the firstembodiment) and other paired user devices involved in the multi-usercommunication report the DMRS configuration information to the networkcontrol device, after the DMRS configurations are determined. The DMRSconfiguration information reported by the user device can include: DMRSport number or the user device, the scrambling code sequence number, thecell number, the time-frequency mapping location, and the like. Suchreporting process can be completed during a prescheduling for themulti-user communication, and the DMRS configuration informationreported by all user devices are saved at the network control device.

Then, the present user device transmits a DMRS configuration informationrequest R1 to the network control device. In response to receiving therequest R1, the network control device transmits the DMRS configurationinformation to the present user device. Since the present user devicehas saved the information related to its own DMRS configuration, thenetwork control device needs to transmit the DMRS configurationinformation of other paired user devices except the present user device,to reduce an amount of the transmission.

Next, after having acquired the DMRS configuration information of theother paired user devices, the present user device can decide acorrelation degree between the scrambling code sequences of its m (m≥1)DMRS ports and the scrambling code sequences of DMRS ports (n in total,n≥1) of each paired user device.

For example, a dot product of the scrambling code sequence of each DMRSport of the present user device and the scrambling code sequence of eachDMRS port of the other paired user device can be calculated, and m×n dotproducts can be obtained in total. In one example, an average can becalculated for the m×n dot products, and the average indicates anoverall correlation degree between the scrambling code sequences. Then,the average is compared with a predetermined threshold, and when theaverage is larger than the predetermined threshold, it can be assumedthat the overall correlation degree between the scrambling codesequences of DMRS ports used by the present user device and by the otherpaired user devices is high, that is, the orthogonality between thelayers used by the present user device and by the other paired userdevices is bad, and it is apt to cause severe inter-layer interferences.Accordingly, the present user device (e.g. the determining unit 203 ofthe electronic device 200) can determine there is a need to use thechannel state feedback with a higher accuracy. When the average issmaller or equal to the predetermined threshold, it can be assumed thatthe orthogonality between the layers used by the present user device andby the other paired user devices is good, and it is not apt to causesevere inter-layer interferences. Accordingly, the present user device(e.g. the determining unit 203 of the electronic device 200) candetermine there is no need to use the channel state feedback with ahither accuracy.

Alternatively, an average can be calculated for a subset of the m×n dotproducts, so as to judge the correlation degree between the scramblingcode sequences for a single DMRS port of the present user device, suchthat it is determined there is a need to use a more accurate channelstate feedback, as long as a certain layer of the present user device isapt to be interfered.

Although an approach of judging the correlation degree of scramblingcode sequences by calculating the dot product of two scrambling codesequences is described above, other approaches can be used, for example,by calculating a cosine similarity, an Euclidean distance or the likebetween two scrambling code sequences.

1.3.2 Determination Process Based on a Degradation Degree of ChannelQuality

In determining if there is a need to perform another type of channelstate feedback or not, it can be based on the degradation degree ofchannel quality of the channel between the user device and the networkcontrol device, in addition to based on the orthogonality betweencommunication resources used by the user device.

When the wireless channel between the user device and the networkcontrol device is interfered, it may be likely to cause a degradation ofthe channel state and a reduction of the channel quality, such that theaccuracy of the channel state feedback is reduced. For example, when theuser device is switched from a single-user communication to a multi-usercommunication (e.g. MU MIMO), the channel of the present user device isapt to be interfered by the communication of other user devices.Therefore, it can be determined whether there is a need to employ a moreaccurate channel state feedback by detecting the degradation degree ofthe channel quality.

FIG. 4B illustrates a flowchart of an example of the determinationprocess based on the degradation degree of the channel quality.

First, during the multi-user communication such as MU MIMO involving theuser device, the network control device allocates CSI-RS resources forchannel state feedback to the user device, and the user device canacquire CSI such as CQI based on the CSI-RS resources. The CQI acquiredat this time indicates a channel quality during the multi-usercommunication of the user device, and is denoted as MU_CQI.

Thereafter, the user device can calculate a difference between theMU-CQI and a CQI acquired during a single-user communication before themulti-user communication, ΔCQI=SU_CQI−MU_CQI, wherein ΔCQI indicates thedegradation degree of the channel quality of the user device during themulti-user communication due to inter-user interferences, relative tothe channel quality during the single-user communication.

Then, the user device can determine whether there is a need to employanother type of channel state feedback based on ΔCQI. For example, ifΔCQI is larger than a predetermined threshold, it can be assumed thatthe channel quality may be degraded enough to affect the accuracy ofchannel state feedback, and accordingly, the user device (e.g. thedetermining unit 203 of the electronic device 200) can determine whetherthere is a need to use a more accurate channel state feedback. On thecontrast, if ΔCQI is not larger than the predetermined threshold, it canbe assumed that the channel quality has not been degraded enough toaffect the accuracy of the channel state feedback, and accordingly, theuser device can determine there is no need to change the type of channelstate feedback.

1.3.3 Pre-Determination Process

In the first embodiment, during determining whether there is a need toperform another type of channel state feedback, in addition toperforming the determination process as in FIG. 4A or FIG. 4B, thepre-determination process can be performed first, and then thedetermination process as in FIG. 4A or FIG. 4B is performed. Wherein thepre-determination process aims at coarsely evaluating the currentchannel state, so as to decide whether it is necessary to perform thesubsequent determination process.

FIG. 4C illustrates a signaling flowchart of an example of thepre-determination process during a pre-scheduling of the multi-usercommunication according to the first embodiment, in which theprescheduling means that the network control device of a communicationsystem tests different scheduling solutions for the multi-usercommunication so as to find the optimum one, including the optimumallocation of communication resources (e.g. time and frequencyresources) or the like.

As illustrated in FIG. 4C, the prescheduling of the multi-usercommunication such as the MU MIMO takes place in a period of Lsubframes. During each prescheduling, the network control deviceallocates CSI-RS resources to the user device, and the user device canmeasure CQI under the current scheduling solution by using the allocatedCSI-RS resources.

After the completion of the L preschedulings, the user device can obtainL CQIs. Then the user device can count the number of CQIs which aresmaller than a predetermined value, among the L CQIs. If the CQIssmaller than the predetermined value exceed a certain number, forexample, exceed L/2 (here L/2 is just an example, and the number can beany other appropriate number), it can be assumed that the overallchannel quality during the entire prescheduling is not satisfactory, andthere is a possibility that: in the multi-user communication performedformally later, severe inter-user interferences are likely to occur evenin accordance with the optimum scheduling solution. In this case, basedon the result of the pre-determination process, the determinationprocess as shown in FIG. 4A or 4B can be performed, so as to reach afinal determination of whether there is a need to change the type ofchannel state feedback.

If CQIs smaller than the predetermined value do not exceed L/2, it canbe assumed that the scheduling solution for the multi-user communicationin question will not bring severe inter-user interferences, and it isnot necessary to perform the determination process as shown in FIG. 4Aor 4B, so as to reduce processing overhear or signaling overhead.

By performing the pre-determined process as described above, thedetermination process regarding whether there is a need to change thetype of channel state feedback can be reduced, especially in the casewhere the scheduling solution of the multi-user communication will notbring large channel interferences.

1.4 Notifying Process According to the First Embodiment

As described in the above section, the notifying unit 204 of theelectronic device 200 can notify the determination result made by thedetermining unit 203 regarding changing the type of channel statefeedback to the network control device (e.g. the electronic device 300).The notifying can be implemented by transmitting information indicatingthe category of the second type of channel state feedback.

In one example, the indicative information CSI_TYPE_Flag on the categoryof the second type of channel state feedback can be included in anuplink signaling message, for example, the uplink control information(UCI) transmitted via PUCCH or PUSCH, or the CSI packet transmitted viaPUSCH. Preferably, the indicative information CSI_TYPE_Flag can beincluded in the UCI, for example, in a field of the UCI that is unusedat present, or in a newly added field of the UCI (e.g. a newly addedportion at the beginning, at the middle, at the end of the UCI).

Alternatively, the indicative information CSI_TYPE_Flag can be includedin a newly defined uplink signaling message find transmitted via PUCCHor PUSCH to the network control device. The uplink signaling message hasat least a field containing the indicative information CSI_TYPE_Flag.

After receiving the signaling message containing the indicativeinformation CSI_TYPE_Flag, the network control device can learn whichtype of channel state feedback is to be performed, for allocatingcorresponding CSI-RS resources.

The indicative information CSI_TYPE_Flag can be represented by only afew bits.

In one example, the indicative information CSI_TYPE_Flag can berepresented by 1 bit, for example, when CSI_TYPE_Flag=0, it means thechannel state feedback with a low accuracy is to be performed, and onlychannel state information such as CQI, PMI, CRI or the like will bereported, and when CSI_TYPE_Flag=1, it means a more accurate channelstate feedback is to be performed, for example, the precoded feedbackbased on linearly combined codebook, the feedback for covariance matrix,the hybrid CSI feedback or the like. After receiving the indicativeinformation CSI_TYPE_Flag=1, the network control device can decide whichtype of channel state feedback on its own and allocate correspondingCSI-RS resources, as long as the accuracy of CSI is improved.

In a preferred example, the indicative information CSI_TYPE_Flag can berepresented by 2 bits, for example, as shown in the following table:

TABLE 1 correspondence of the bit value and the indicative informationBit value 00 01 10 11 Indication Conventional Precoded Covariance matrixHybrid CSI info. channel state feedback feedback feedback feedback basedon linearly combined codebook

Note that, the above table is only illustrative, and the correspondenceof the bit value and the indicative information is not limited thereto.

In another example, the indicative information CSI_TYPE_Flag can berepresented by more than 2 bits, to possess a feasibility of beingcompatible with more categories of the channel state feedback.

1.5 Application Example According to the First Embodiment

Aspects of the first embodiment have been described above, andhereinafter description will be given to the application example underthe MU MIMO communication scenario with reference to FIG. 5. Althoughthis application example takes MU MIMO communication scenario intoaccount, but it is also applicable to other multi-user communicationscenarios.

Before the start of the MU MIMO communication, the user device canmeasure a receiving power of non-zero-power CSI-RS, i.e., referencesignal receiving power (RSRP), and only when the RSRP is larger than athreshold P′, P′ being a maximum of the RSRPs of users at edge of acell, it can be assumed that the user device is not at edge of the cell,and the MU MIMO communication can be performed.

After determining the user device can perform the MU MIMO communication,the network control device can perform prescheduling for the user deviceand other user devices which are close geographically to each other, soas to determine an optimum scheduling solution of the MU MIMO for theseuser devices, as shown in FIG. 5.

After the completion of the pre-scheduling, the network control devicecan implement the MU MIMO transmission according to the optimumscheduling solution.

During the MU MIMO transmission, the network control device can allocatethe first type of CSI-RS resources to the use device, and the userdevice acquires the first type of CSI using the CSI-RS resources andreports the acquired CSI to the network control device for use.

Meanwhile, the user device can perform the determination processregarding whether there is a need to perform the second type of channelstate feedback. For example, the user device can perform thedetermination process as shown in FIG. 4A or 4B, or alternatively, canperform the pre-determination process as shown in FIG. 4C at first, andthen perform the determination process as shown in FIG. 4A or 4B. Whenthe user device has determined that there is a need to change the typeof the channel state feedback and determine the specific category of thechannel state feedback, a notification including the determinationresult can be generated and sent to the network control device, forexample by using the notifying process as described above in the Section1.4.

The network control device, alter receiving the notification, can learnthe category of the channel state feedback to be performed, and allocatethe second type of CSI-RS resources to the user device. Simultaneouslywith allocating the second type of CSI-RS resources, the network controldevice can stop allocating the first type of CSI-RS resources.Alternatively, the network control device can continue to allocate thefirst type of CSI-RS resources while allocating the second type ofCSI-RS resources.

Then, the user device can use the second type of CSI-RS resources toacquire the second type of CSI, and report the acquired second type CSIto the network control device. While reporting the second type of CSI,the user device may stop reporting the first type of CSI in response tothe network control device stopping allocation of the first type ofCSI-RS resources, or alternatively, can continue to report the firsttype of CSI in response to the network control device continuingallocation of the first type of CSI-RS resources.

2. The Second Embodiment

In the first embodiment as described above, the determination processregarding whether there is a need to change the type of channel statefeedback is performed on the side of user, but the determination processcan also be performed on the side of network control.

The second embodiment of the present disclosure will be described withreference to the drawings. The following description focuses ondifferent portions from the first embodiment, and the description of thesame portions will be omitted or simplified.

2.1 The Electronic Device on the Side of Network Control and ItsCommunication Method According to the Second Embodiment

The electronic device 600 on the side of network control and itscommunication method according to the second embodiment will bedescribed below with reference to FIG. 6A and FIG. 6B.

FIG. 6A is a block diagram illustrating the electronic device 600according to the second embodiment. The electronic device 600 is a basestation such as eNB in the 4G communication standard or gNB in the 5Gcommunication standard, or a communication means performing similarfunctionalities. The electronic device 600 includes at least aprocessing circuitry 601. The processing circuitry 601 provides variousfunctionalities of the electronic device 600. For example, theprocessing circuitry 601 can include an allocating unit 602, adetermining unit 603 and a notifying unit 604.

The allocating unit 602 of the electronic device 600 is configured toallocate resources for channel state feedback to a user device (e.g. theelectronic device 700 as described below) depending to the type of thechannel state feedback. The resources for channel state feedback can bevarious downlink reference signals or pilot signal, such as CRS, CSI-RSor the like. The allocating unit 602 can allocate reference signals fordifferent types of channel state feedback. For example, the allocatingunit 602 can allocate CSI-RS resources periodically, for the user deviceto measure conventional CSI such as CQI, PMI, RI and the like. However,if the determining unit 603 as described below determines that anenhanced channel state feedback is to be performed, the resources forthe enhanced channel state feedback can be allocated by the allocatingunit 602.

The determining unit 603 of the electronic device 600 is configured todetermine whether there is a need to change the type of the channelstate feedback. The determining unit 603 can perform such determinationprocess based on various factors, including requirements a communicationservice has on the content or accuracy of the CSI, channel interferencessuch as inter-user interferences, overhead on the processing andtransmission of CSI, or the like. In the present disclosure, assumingthat the current channel state feedback is of a first type and is usedto report the first type of CSI. The determining unit 603 can determinea second type of channel state feedback is to be used to report thesecond type of CSI. The determining unit 603 further determines thespecific category of the second type of channel state feedback.

The notifying unit 604 is configured to notify the user device (forexample, the electronic device 700 as described below) of thedetermination result made by the determining unit 603. The notifyingunit 604 can perform the notifying by generating a message including thedetermination result and send it to the user device. For example, thedetermination result can be included in downlink control information(DCI) signaling transmitted via physical downlink control channel(PDCCH), or can be included in a newly defined downlink signalingmessage to be transmitted to the user device via the PDCCH. Theinformation on the determination result may indicate the specificcategory of the channel state feedback which is desired to be performednext, and thus the network control device can know which channel statefeedback is to be performed next upon receiving the notification issuedby the notifying unit 604, and can acquire and report the second type ofCSI by employing corresponding resources to (e.g. CSI-RS) for channelstate feedback.

The electronic device 600 can further include a communication unit 605and a memory 606.

The communication unit 605 of the electronic device 600 can beconfigured to communicate with the user device under control of theprocessing circuitry 601. The communication unit 605 can be implementedas a transceiver. In one example, the communication unit 605 can beimplemented as a communication interface component of an antenna device,a radio frequency circuit, and the like. The communication unit 605 isdepicted with broken lines, since it can also reside within theprocessing circuitry 601 or outside the electronic device 600.

The memory 606 of the electronic device 600 can store variousinformation generated by the processing circuitry 601, program or dataused by the electronic device 600 to operate, data or information to betransmitted by the communication unit 605. The memory 606 is depicted bybroken lines, since it can also reside within the processing circuitry601 or outside the electronic device 300. The memory 606 can be avolatile memory and/or a non-volatile memory. For example, the memory606 can include but is not limited to a random access memory (RAM), adynamic random access memory (DRAM), a static random access memory(SRAM), a read only memory (ROM), a flash memory.

The communication method performed by the electronic device 600 will bedescribed below with reference to FIG. 6B.

As shown in FIG. 6B, in step S61, the allocating unit 602 of theelectronic device 600 allocates resources for the first type of channelstate feedback to the user device. For example, in one example, thenetwork control device can allocate periodic CSI-RS resources to theuser device (e.g. the electronic device 700 as described below), for theuser device to report periodically channel state information such asCQI, PMI, RI or the like.

Then in step S62, the determining unit 602 of the electronic device 600determines whether to perform the second type of channel state feedback,wherein the second type is different from the first type. Thedetermination process can be performed based on various factors, andexamples of the determination process will be described in detail laterin the following Section 2.3. If the determining unit 603 determinesthat the second type of channel state feedback is to be performed, thedetermination result and information on the specific category of thesecond type of channel state feedback are presented to the notifyingunit 604. If the determining unit 603 determines that the type of thechannel state feedback needs not to be changed, the reporting unit 602will continue to perform the first type of channel state feedback.

In step S63, the notifying unit 604 of the electronic device 600notifies the user device of the determination result made by thedetermining unit 603. Such notifying process can be implemented bygenerating and transmitting a message including the specific category ofthe second type of channel state feedback. Specific examples of thenotifying process will be described in the following Section 2.4.

Next, in step S64, the allocating unit 602 of the electronic device 600can start allocating the resources for the second type of channel statefeedback, based on the determination result made by the determining unit603, such the user device can acquire and report the second type of CSI.

2.2 The Electronic Device on the Side of User and Its CommunicationMethod According to the Second Embodiment

The electronic device 700 on the side of user and its communicationmethod according to the second embodiment will be described below withreference to FIGS. 7A and 7B.

FIG. 7A is a block diagram illustrating the electronic device 700according to the second embodiment. The electronic device 200 is a userdevice such as a mobile phone, an in-vehicle device, a tablet or thelike or its element. As illustrated in FIG. 7A, electronic device 700includes at least a processing circuitry 701. The processing circuitry701 of the electronic device 700 provides various functionalities of theelectronic device 200. For example, the processing circuitry 701 caninclude a reporting unit 702 and a notification receiving unit 703.

The reporting unit 702 is configured to acquire and report CSI by usinga resource for channel state feedback allocated by the network controldevice (e.g. the electronic device 600 as described above). Thereporting unit 702 may perform the channel state feedback in manymanners. For example, the reporting unit 702 may perform the channelstate feedback in an implicit manner, that is, report to the networkcontrol device information characterizing the channel state, such asCQI, PMI, RI, CRI or the like. Alternatively, the reporting unit 702 canperform an explicit reporting, including the precoded feedback based onlinearly combined codebook, the feedback for channel covariance matrix,the hybrid CSI feedback or the like.

The notification receiving unit 703 of the electronic device 700 isconfigured to receive the notification regarding whether it is requiredto perform another type of channel state feedback from the networkcontrol device. This notification can include information on thespecific category of the channel state feedback to be performed by theelectronic device 700, and based on this information, the reporting unit702 of the electronic device 700 can report corresponding CSI, for useby the network control device, for example, for use in performingresource scheduling or precoding.

The electronic device 700 can further include a communication unit 705and a memory 706.

The communication unit 705 of the electronic device 700 can beconfigured to communicate with the user device under control of theprocessing circuitry 701, so as to transmit CSI or the like to thenetwork control device. The communication unit 705 can be implemented asa transmitter or transceiver. In one example, the communication unit 705can be implemented as a communication interface component of an antennadevice, a radio frequency circuit, and the like. The communication unit705 is depicted with broken lines, since it can also reside within theprocessing circuitry 701 or outside the electronic device 700.

The memory 706 of the electronic device 700 can store variousinformation generated by the processing circuitry 701, program or dataused by the electronic device 700 to operate, data or information (e.g.CSI) to be transmitted by the communication unit 705. The memory 706 isdepicted by broken lines, since it can also reside within the processingcircuitry 701 or outside the electronic device 700. The memory 706 canbe volatile memory and/or non-volatile memory. For example, the memory706 can include but is not limited to a random access memory (RAM), adynamic random access memory (DRAM), a static random access memory(SRAM), a read only memory (ROM), a flash memory.

FIG. 7B illustrates the communication method performed by the electronicdevice 700 on the side of user.

As illustrated in FIG. 7B, in step S71, the reporting unit 702 of theelectronic device 700 can report the first type of CSI by using theresources for the first type of channel state feedback allocated by thenetwork control device. The type of the channel state feedback performedby the reporting unit 702 is associated with the resource allocated bythe network control device. For example, in one example, the networkcontrol device can allocate periodic CSI-RS resources to the electronicdevice 700, such that the reporting unit 702 can measure for exampleCQI, parameters related to the channel matrix or the like by using theCSI-RS resources, and periodically report the CSI to the network controldevice.

In step S72, the notification receiving unit 703 of the electronicdevice 700 receives from the network control device the notificationthat there is a need to perform the second type of channel statefeedback. Information included in the notification is extracted, andthus the indicative information on the specific category of the secondtype of channel state feedback can be obtained.

In step S73, based on the indicative information extracted from thenotification, the reporting unit 702 of the electronic device 700performs the second type of channel state feedback, and reports theacquired CSI to the network control device.

2.3 The Determination Process According to the First Embodiment

In the first embodiment of the present disclosure, the determinationprocess of determining whether there is a need to perform anotherchannel state feedback of the type different from that of the currentchannel state feedback is done at the device on the side of networkcontrol (e.g. the electronic device 600). The determination process canbe performed in consideration of various factors. For purpose ofillustration, an example of such determination process implemented inthe multi-user communication scenario is described in detail below. Asused herein, the multi-user communication for example is the MU MIMOcommunication.

In the MU MIMO communication, depending on the orthogonality between thelayers used by respective user devices, there is inter-layerinterference to some extent. When the inter-layer interference issevere, the performance of transmission of the MU MIMO communication isreduced, which may cause the accuracy of the CSI to decrease. Byevaluating such inter-layer interference, it can be decided whether thecurrent channel state feedback meets the need or not.

2.3.1 Determination Process Based on the Orthogonality BetweenCommunication Resources

As explained in the above Section 1.3.1, the determination processregarding whether there is a need to change the type of the channelstate feedback can be performed based on the orthogonality between thecommunication resources used by the user devices.

In one example, the orthogonality can be decided based on demodulationreference signal (DMRS) ports corresponding to layers of respective userdevices, wherein the DMRS ports can be indicated by correspondingscrambling code sequences. The orthogonality between layers used bydifferent user devices may be decided by evaluating a correlation degreebetween the scrambling code sequences of respective DMRS ports.

FIG. 8A is signaling flowchart of an example of the determinationprocess based on DMRS configuration information.

First, as shown by the dotted arrow, the present user device (the userdevice performing the communication method according to the secondembodiment) and other paired user devices involved in the multi-usercommunication report the DMRS configuration information to the networkcontrol device, after the DMRS configurations are determined. The DMRSconfiguration information reported by the user device can include: theDMRS port number of the user device, the scrambling code sequencenumber, the cell number, the time-frequency mapping location, and thelike. Such reporting process can be completed during a prescheduling forthe multi-user communication, and the DMRS configuration informationreported by all user devices are saved at the network control device.

Then, the network control device can evaluate the orthogonality betweenthe communication resources used by respective user devices based on theDMRS configuration reported by the user devices. The network controldevice can decide the correlation degree between the scrambling codesequences of m (m≥1) DMRS ports of the present user device and thescrambling code sequences of DMRS ports (n in total, n≥1) or otherpaired user devices.

For example, a dot product of the scrambling code sequence of each DMRSport of the present user device and the scrambling code sequence of eachDMRS port of other paired user devices can be calculated, and m×n dotproducts can be obtained in total. In one example, an average can becalculated for the m×n dot products, and the average indicates anoverall correlation degree between the scrambling code sequences. Then,the average is compared with a predetermined threshold, and when theaverage is larger than the predetermined threshold, it can be assumedthat the overall correlation degree between the scrambling codesequences of DMRS ports used by the present user device and by the otherpaired user devices is high, that is, the orthogonality between thelayers used by the present user device and by the other paired userdevices is bad, and it is apt to cause severe inter-layer interferences,and accordingly, the present user device (e.g. the determining unit 603of the electronic device 600) can determine there is a need to use thechannel state feedback with a higher accuracy. When the average issmaller or equal to the predetermined threshold, it can be assumed thatthe orthogonality between the layers used by the present user device andby the other paired user devices is good, and it is not apt to causesevere inter-layer interferences, and accordingly, the present userdevice (e.g. the determining unit 603 or the electronic device 600) candetermine there is no need required to use the channel state feedbackwith a higher accuracy.

Alternatively, an average can be calculated for a subset of the m×n dotproducts, so as to judge the correlation degree between the scramblingcode sequences for a single DMRS port of the present user device, suchthat it is determined there is a need to use a more accurate channelstate feedback, as long as a certain layer of the present user device isapt to be interfered.

Although an approach of deciding the correlation degree of scramblingcode sequences by calculating the dot product of two scrambling codesequences is described above, other approaches can be used, for example,by calculating a cosine similarity, an Euclidean distance or the likebetween two scrambling code sequences.

2.3.2 Determination Process Based on the Degradation Degree of ChannelQuality

In determining if there is a need to perform another type of channelstate feedback or not, it can be based on the degradation degree ofchannel quality of the channel between the user device and the networkcontrol device, in addition to being based on the orthogonality betweencommunication resources used by the user device.

FIG. 8B illustrates a signaling flowchart of an example of thedetermination process based on the degradation degree of channelquality.

First, during the multi-user communication involving the user device,such as the MU MIMO, the network control device allocates CSI-RSresources for channel state feedback to the user device, and the userdevice can acquire the CSI including CQI, based on the CSI-RS resources.The CQI acquired at this time indicates a channel quality during themulti-user communication of the user device, and is denoted as MU_CQI.

Thereafter, the network control device can calculate a differencebetween the MU-CQI and a CQI acquired during a single-user communicationbefore the multi-user communication, ΔCQI=Su_CQI−MU_CQI, wherein ΔCQIindicates the degradation degree of the channel quality of the userdevice during the multi-user communication due to inter-userinterferences, relative to the channel quality during the single-usercommunication.

Then, the network control device can determine whether there is a needto use another type of channel state feedback based on ΔCQI. Forexample, if ΔCQI is larger than a predetermined threshold, it can beassumed that the channel quality may be degraded enough to affect theaccuracy of channel state feedback, and accordingly the user device(e.g. the determining unit 603 of the electronic device 600) maydetermine whether there is a need to use a more accurate channel statefeedback. On the contrast, if ΔCQI is not larger than the predeterminedthreshold, it can be assumed that the channel quality has not beendegraded enough to affect the accuracy of the channel state feedback,and accordingly, the user device may determine there is no need tochange the type of channel state feedback.

2.3.3 Pre-Determination Process

In the second embodiment, during determining whether there is a need toperform another type of channel state feedback, in addition toperforming the determination process as in FIG. 8A or FIG. 8B, thepre-determination process can be performed at first, and then thedetermination process as in FIG. 8A or FIG. 8B is performed. Wherein thepre-determination process aims at coarsely evaluating the currentchannel state, so as to decide whether it is necessary to perform thesubsequent determination process.

FIG. 8C illustrates a signaling flowchart of an example of thepre-determination process during a prescheduling of the multi-usercommunication according to the second embodiment.

As illustrated in FIG. 8C, the prescheduling of the multi-usercommunication such as MU MIMO takes place in a period of L subframes.During each prescheduling, the network control device allocates CSI-RSresources to the user device, and the user device can measure CQI underthe current scheduling solution by employing the allocated CSI-RSresources.

After the completion of L preschedulings, the user device can obtain LCQIs. Then the user device can count the number of CQIs which aresmaller than a predetermined value, among the L CQIs. If the CQIssmaller than the predetermined value exceed a certain number, forexample, exceed L/2 (here L/2 is just an example, and the number can beany other appropriate number), it can be assumed that the overallchannel quality during the entire pre-scheduling is not satisfactory,and there is a possibility that: in the multi-user communicationperformed formally later, several inter-user interferences are likely tooccur even in accordance with the optimum scheduling solution. In thiscase, based on the result of the pre-determination process, thedetermination process as shown in FIG. 8A or 8B can be performed, so asto reach a final determination of whether there is a need to change thetype of channel state feedback.

If CQIs smaller than the predetermined value do not exceed L/2, it canbe assumed that the scheduling solution for the multi-user communicationin question will not bring severe inter-user interferences, and it isnot necessary to perform the determination process as shown in FIG. 8Aor 8B, so as to reduce processing overhear or signaling overhead.

By performing the pre-determined process as described above, thedetermination process regarding whether there is a need to change thetype of channel state feedback can be reduced, especially in the casewhere the scheduling solution of the multi-user communication will notbring large channel interferences.

2.4 Notification Process According to the First Embodiment

As described in the above sections, the notifying unit 604 of theelectronic device 600 can notify the determination result made by thedetermining unit 603 regarding changing the type of channel statefeedback to the user device (e.g. the electronic device 700). Thenotifying can be implemented by transmitting information indicating thecategory of the second type of channel state feedback.

In one example, the indicative information CSI_TYPE_Flag on the categoryof the second type of channel state feedback can be included in adownlink signaling message, for example, the downlink controlinformation (DCI) transmitted via the PDCCH. Preferably, the indicativeinformation CSI_TYPE_Flag can be included in the DCI, for example, in afield of the DCI that is unused at present, or in a newly added field ofthe DCI (e.g. a newly added portion at the beginning, at the middle, atthe end of the DCI).

Alternatively, the indicative information CSI_TYPE_Flag can be includedin a newly defined downlink signaling message.

After receiving the signaling message containing the indicativeinformation CSI_TYPE_Flag, the user device can learn which type ofchannel state feedback is to be performed, and perform the channel statefeedback by using corresponding CSI-RS resources allocate by the networkcontrol device.

With respect to the indicative information CSI_TYPE_Flag, it can berepresented by several bits. The representations for the indicativeinformation CSI_TYPE_Flag have been described in the above Section 1.4,and detailed description thereof will be omitted here.

2.5 Application Example According to the Second Embodiment

Aspects of the second embodiment have been described above, andhereinafter description will be given to the application example underthe MU MIMO communication scenario with reference to FIG. 9. Althoughthis application example takes the MU MIMO communication scenario intoaccount, but it is also applicable to other multi-user communicationscenario.

Before the start of the MU MIMO communication, the user device canmeasure a receiving power of non-zero-power CSI-RS, i.e., referencesignal receiving power (RSRP), and only when the RSRP is larger than athreshold P′, wherein P′ is a maximum of the RSRPs of users at edge of acell, it can be assumed that the user device is not at edge of the cell,and the MU MIMO communication can be performed.

After determining the user device can perform the MU MIMO communication,the network control device can perform a prescheduling for the userdevice and other user devices which are close geographically to eachother, so as to determine an optimum scheduling solution of the MU MIMOfor these user devices, as shown in FIG. 9.

After the completion of the pre-scheduling, the network control devicecan carry out the MU MIMO transmission according to the optimumscheduling solution.

During the MU MIMO transmission, the network control device can allocatethe first type of CSI-RS resources to the use device, and the userdevice acquires the first type of CSI using the CSI-RS resources andreports the acquired CSI to the network control device for use.

Meanwhile, the network control device can perform the determinationprocess regarding whether it is required to perform the second type ofchannel state feedback. For example, the user device can perform thedetermination process as shown in FIG. 8A or 8B, or alternatively, canperform the pre-determination process as shown in FIG. 8C at first, andthen perform the determination process as shown in FIG. 8A or 8B. Whenthe network control device has determined that it is required to changethe type of the channel state feedback and determine the specificcategory of the channel state feedback, the determination result can benotified to the user device, for example by using the notifying processas described above in the section 2.4.

The user device, after receiving the notification, can learn thecategory of the channel state feedback to be performed, and acquire thesecond type of CSI by using the second type of CSI-RS resourcesallocated by the network control device. Simultaneously with reportingthe second type of CSI-RS resources, the network control device can stopreporting the first type of CSI in response to the network controldevice stopping the allocation of the first type of CSI-RS resources.Alternatively the user device can continue to report the first type ofCSI in response to the network control device continuing allocating thefirst type of CSI-RS resources.

3. Application Example of the Present Application

Technology according the present application is applicable to variousproducts.

For example, the electronic device 300 or 600 according to theembodiments of the present disclosure may be implemented as variousnetwork control devices or stalled in various network control devices,and the electronic device 200 or 700 according to the embodiments of thepresent disclosure may be implemented as various user devices or stalledin various user devices, or the communication methods according to theembodiments of the present disclosure can be implemented by variousnetwork control devices or user devices.

The network control device may be implemented as any type of basestations, preferably, such as the macro gNB or the small gNB in the NR(New Radio) access technology of the 3GPP 5G communication standard. Asmall gNB may be an gNB that covers a cell smaller than a macro cell,such as a pico gNB, micro gNB, and home (femto) gNB. Instead, thenetwork control device may be implemented as any other types of basestations such as a NodeB, eNodeB and a base transceiver station (BTS).The network control device may include a main body (that is alsoreferred to as a base station device) configured to control wirelesscommunication, and one or more remote radio heads (RRH) disposed in adifferent place from the main body.

The user device may be implemented as a mobile terminal such as asmartphone, a tablet personal computer (PC), a notebook PC, a portablegame terminal, a portable/dongle type mobile router, and a digitalcamera apparatus, or an in-vehicle terminal such as a car navigationdevice. The user device may also be implemented as a terminal (that isalso referred to as a machine type communication (MTC) terminal) thatperforms machine-to-machine (M2M) communication. Furthermore, the userdevice may be a wireless communication module (such as an integratedcircuit module including a single die) mourned on each of the aboveterminals.

3.1 Applications Related to Electronic Device on the Side of ControlDevice

It will be appreciated that as used in the present disclosure, the term“network control device” or “base station” has the entire breadth in itsgeneric sense, and includes at least the wireless communication stationused for a portion of a wireless communication system or a radio systemfor purpose of communication. Examples of the base station can be forexample but is not limited to the following: the base station can beeither or both of the base transceiver station (BTS) and the basestation controller (BSC) in the GSM system, can be either or both of theradio network controller (RNC) or NodeB in the WCDMA system, can be eNBin the LTE and LTE-Advanced system, or can be corresponding networknodes in future communication systems (for example, the gNB possiblyappearing in the 5G communication system, or the like). In communicationscenarios such as D2D, M2M and V2V, a logical entity having a controlfunction over the communication can be referred to a base station. Inthe scenario of cognitive radio communication, a logical entity having afunction of frequency spectrum coordination can also be referred to abase station.

First Application Example

FIG. 10 is a block diagram illustrating a first example of a schematicconfiguration of the network control device to which a technology of thepresent application may be applied. The network control device mayinclude for example the electronic device 300 or 600 for downlinktransmission. In FIG. 10, the network control device is illustrated asan gNB 800. The gNB 800 includes a plurality of antennas 810 and a basestation device 820. The base station device 820 and each antenna 810 maybe connected with each other via a RF cable.

The antennas 810 may include one or more antenna arrays, which includesmultiple antenna elements (such as multiple antenna elements included ina Multiple Input and Multiple Output (MIMO) antennas), and is used forthe base station 820 to transmit and receive radio signals. The gNB 800may include multiple antennas 810, as illustrated in FIG. 10. Forexample, multiple antennas 810 may be compatible with multiple frequencyhands used by the gNB 800. FIG. 10 illustrates the example in which thegNB 800 includes multiple antennas 810.

The base station device 820 includes a controller 821, a memory 822, anetwork interface 823, and a radio communication interface 825.

The controller 821 may be, for example, a CPU or a DSP, and operatesvarious functions of a higher layer of the base station device 820. Forexample, the controller 821 may include the processing circuitry 301 or601 as described above, perform the communication method on the side ofnetwork control as described in the above first or second embodiment, orcontrol the components of the electronic device 300 or 600. For example,the controller 821 generates a data packet from data in signalsprocessed by the radio communication interface 825, and transfers thegenerated packet via the network interface 823. The controller 821 maybundle data from multiple base band processors to generate the bundledpacket, and transfer the generated bundled packet. The controller 821may have logical functions of performing control such as radio resourcecontrol, radio bearer control, mobility management, admission control,and scheduling. The control may be performed in corporation with an gNBor a core network node in the vicinity. The memory 822 includes RAM andROM, and stores a program that is executed by the controller 821, andvarious types of control data such as a terminal list, transmissionpower data, and scheduling data.

The network interface 823 is a communication interface for connectingthe base station device 820 to a core network 821. The controller 821may communicate with a core network node or another gNB via the networkinterface 823. In that case, the gNB 800, and the core network node orthe other gNB may be connected to each other through a logical interfacesuch as an S1 interface and an X2 interface. The network interface 823may also be a wired communication interface or a radio communicationinterface for radio backhaul. If the network interface 823 is a radiocommunication interface, the network interface 823 may use a higherfrequency band for radio communication than a frequency band used by theradio communication interface 825.

The radio communication interface 825 supports any cellularcommunication scheme such as Long Term Evolution (LTE) and LTE-Advanced,and provides radio connection to a terminal positioned in a cell of thegNB 800 via the antenna 810. The radio communication interface 825 maytypically include, for example, a baseband (BB) processor 826 and an RFcircuit 827. The BB processor 826 may perform, for example,encoding/decoding, modulating/demodulating, andmultiplexing/demultiplexing, and performs various types of signalprocessing of layers such as L1, medium access control (MAC), radio linkcontrol (RLC), and a packet data convergence protocol (PDCP). The BBprocessor 826 may have a part or all of the above-described logicalfunctions instead of the controller 821. The BB processor 826 may be amemory that stores a communication control program, or a module thatincludes a processor configured to execute the program and a relatedcircuit. Updating the program may allow the functions of the BBprocessor 826 to be changed. The module may be a card or a blade that isinserted into a slot of the base station device 820. Alternatively, themodule may also be a chip that is mounted on the card or the blade.Meanwhile, the RF circuit 827 may include, for example, a mixer, afilter, and an amplifier, and transmits and receives radio signals viathe antenna 810.

The radio communication interface 825 may include the multiple BBprocessors 826, as illustrated in FIG. 10. For example the multiple BBprocessors 826 may be compatible with multiple frequency bands used bythe gNB 800. The radio communication interface 825 may include themultiple RF circuits 827, as illustrated in FIG. 10. For example, themultiple RF circuits 827 may be compatible with multiple antennaelements. Although FIG. 10 illustrates the example in which the radiocommunication interface 825 includes the multiple BB processors 826 andthe multiple RF circuits 827, the radio communication interface 825 mayalso include a single BB processor 826 or a single RF circuit 827.

In the gNB 800 illustrated in FIG. 10, one or more of the components(for example, the allocating unit 302, 602) included in the processingcircuitry 301 described with reference to FIG. 3A or the processingcircuitry 601 described with reference to FIG. 6A may be implemented inthe radio communication interface 825. Alternatively, at least a part ofthese components may be implemented in the controller 821. As anexample, the gNB 800 includes a part (for example, the BB processor 826)or the entire of the radio communication interface 825 and/or a moduleincluding the controller 821, and the one or more components may beimplemented in the module. In this case, the module may store a program(in other words, a program causing the processor to execute operationsof the one or more components) causing me processor to function as theone or more components, and execute the program. As another example, aprogram causing the processor to function as the one or more componentsmay be installed in the gNB 800, and the radio communication interface825 (for example, the BB processor 826) and/or the controller 821 mayexecute the program. As described above, as a device including the oneor more components, the gNB 800, the base station device 820 or themodule may be provided. In addition, a readable medium in which theprogram is recorded may be provided.

Second Application Example

FIG. 11 is a block diagram illustrating a second example of a schematicconfiguration of the network control device to which a technology of thepresent application may be applied. The network control device caninclude for example the electronic device 300 or 600 for downlinktransmission. In FIG. 11, the network control device is illustrated asgNB 830. The gNB 830 includes one or more antennas 840, a base stationdevice 850, and an RRH 860. Each antenna 840 and the RRH 860 may beconnected to each other via an RF cable. The base station device 850 andthe RRH 860 may be connected to each other via a high speed line such asan optical fiber cable.

The antennas 840 includes one or more antenna arrays as described above,and the antenna array includes multiple antenna elements such asmultiple antenna elements included in an MIMO antenna and is used forthe RRH 860 to transmit and receive radio signals. The gNB 830 mayinclude multiple antennas 840, as illustrated in FIG. 11. For example,multiple antennas 840 may be compatible with multiple frequency bandsused by the gNB 830. FIG. 11 illustrates an example in which the gNB 830includes multiple antennas 840.

The base station device 850 includes a controller 851, a memory 852, anetwork interface 853, a radio communication interface 855, and aconnection interface 857. The controller 851, the memory 852, and thenetwork interface 853 are the same as the controller 821, the memory822, and the network interface 823 described with reference to FIG. 10.

The radio communication interface 855 supports any cellularcommunication scheme such as LTE and LTE-Advanced, and provides radiocommunication to a terminal positioned in a sector corresponding to theRRH 860 via the RRH 860 and the antenna 840. The radio communicationinterface 855 may typically include, for example, a BB processor 856.The BB processor 856 is the same as the BB processor 826 described withreference to FIG. 10, except the BB processor 856 is connected to the RFcircuit 864 of the RRH 860 via the connection interface 857. The radiocommunication interface 855 may include the multiple BB processors 856,as illustrated in FIG. 11. For example, multiple BB processors 856 maybe compatible with multiple frequency bands used by the gNB 830.Although FIG. 11 illustrates the example in which the radiocommunication interface 855 includes multiple BB processors 856, theradio communication interface 855 may also include a single BB processor856.

The connection interface 857 is an interface for connecting the basestation device 850 (radio communication interface 855) to the RRH 860.The connection interface 857 may also be a communication module forcommunication in the above-described high speed line that connects thebase station device 850 (radio communication interface 855) to the RRH860.

The RRH 860 includes a connection interface 861 and a radiocommunication interface 863.

The connection interface 861 is an interface for connecting the RRH 860(radio communication interface 863) to the base station device 850. Theconnection interface 861 may also be a communication module forcommunication in the above-described high speed line.

The radio communication interface 863 transmits and receives radiosignals via the antenna 840. The radio communication interface 863 maytypically include, for example, the RF circuit 864. The RF circuit KMmay include, for example, a mixer, a filler, and an amplifier, andtransmits and receives radio signals via the antenna 840. The radiocommunication interface 863 may include multiple RF circuits 864, asillustrated in FIG. 11. For example, multiple RF circuits 864 maysupport multiple antenna elements. Although FIG. 11 illustrates theexample in which the radio communication interface 863 includes themultiple RF circuits 864, the radio communication interface 863 may alsoinclude a single RF circuit 864.

In the gNB 830 illustrated in FIG. 11, one or more of the components(the allocating 302 or 602) of the processing circuitry 301 describedwith reference to FIG. 3A or the processing circuitry 601 described withreference to FIG. 6A may be implemented in the radio communicationinterface 855. Alternatively, at least a part of these components may beimplemented in the controller 851. As an example, the gNB 830 include apart (for example, the BB processor 836) or the entire of the radiocommunication interface 855 and/or a module including the controller851, and the one or more components may be implemented in the module. Inthis case, the module may store a program (in other words, a programcausing the processor to execute operations of the one or morecomponents) causing the processor to function as the one or morecomponents, and execute the program. As another example, a programcausing the processor to function as the one or more components may beinstalled in the gNB 830, and the radio communication interface 855 (forexample, the BB processor 856) and/or the controller 851 may execute theprogram. As described above, as a device including the one or morecomponents, the gNB 830, the base station device 850 or the module maybe provided. A program causing the processor to function as the one ormore components may also be provided. In addition, a readable medium inwhich the program is recorded may be provided.

3.2 Applications Related in Electronic Device on the User Side FirstApplication Example

FIG. 12 is a block diagram illustrating an example of a schematicconfiguration of a smartphone 900 to which a technology of the presentapplication may be applied. Wherein, the smart phone 900 can beimplemented as the electronic device 200 described with reference toFIG. 2A or the electronic device 700 described with reference to FIG.7A. The smartphone 900 includes a processor 901, a memory 902, a storage903, an external connection interface 904, a camera 906, a sensor 907, amicrophone 908, an input device 909, a display device 910, a speaker911, a radio communication interface 912, one or more antenna switches915, one or more antennas 916, a bus 917, a battery 918, and anauxiliary controller 919.

The processor 901 may be, for example, a CPU or a system on a chip (SoC)and controls functions of an application layer and the other layers ofthe smartphone 900. The memory 902 includes RAM and ROM, and stores aprogram that is executed by the processor 901, and data. The storage 903may include a storage medium such as a semiconductor memory and a harddisk. The external connection interface 904 is an interface forconnecting an external device such as a memory card and a universalserial bus (USB) device to the smartphone 900.

The camera 906 includes an image sensor such as a charge coupled device(CCD) and a complementary metal oxide semiconductor (CMOS), andgenerates a captured image. The sensor 907 may include a group ofsensors such as a measurement sensor, a gyro sensor, a geomagneticsensor, and an acceleration sensor. The microphone 908 converts thesounds that are input to the smartphone 900 to audio signals. The inputdevice 909 includes, for example, a touch sensor configured to detecttouch onto a screen of the display device 910, a keypad, a keyboard, abutton, or a switch, and receives an operation or an information inputfrom a user. The display device 910 includes a screen such as a liquidcrystal display (LCD) and an organic light-emitting diode (OLED)display, and displays an output image of the smartphone 900. The speaker911 converts audio signals that are output from the smartphone 900 tosounds.

The radio communication interface 912 supports any cellularcommunication scheme such as LTE and LTE-Advanced, and performs radiocommunication. The radio communication interface 912 may typicallyinclude, for example, a BB processor 913 and an RF circuit 914. The BBprocessor 913 may perform, for example, encoding/decoding,modulating/demodulating, and multiplexing/demultiplexing, and performsvarious types of signal processing for radio communication. Meanwhile,the RF circuit 914 may include, for example, a mixer, a filter, and anamplifier, and transmits and receives radio signals via the antenna 916.The radio communication interface 912 may also be a one chip module thatintegrates the BB processor 913 and the RF circuit 914 thereon. Theradio communication interface 912 may induce multiple BB processors 913and multiple RF circuits 914, as illustrated in FIG. 12. Although FIG.12 illustrates the example in which the radio communication interface912 includes multiple BB processors 913 and multiple RF circuits 914,the radio communication interface 912 may also include a single BBprocessor 913 or a single RF circuit 914.

Furthermore, in addition to a cellular communication scheme, the radiocommunication interface 912 may support another type of radiocommunication scheme such as a short-distance wireless communicationscheme, a near field communication scheme, and a wireless local areanetwork (LAN) scheme. In that case, the radio communication interface912 may include the BB processor 913 and the RF circuit 914 for eachradio communication scheme.

Each of the antenna switches 915 switches connection destinations of theantennas 916 among multiple circuits (such as circuits for differentradio communication schemes) included in the radio communicationinterface 912.

Each of the antennas 916 includes a single or multiple antenna elementssuch as multiple antenna elements included in an MIMO antenna, and isused for the radio communication interface 912 to transmit and receiveradio signals. The smartphone 900 may include multiple antennas 916, asillustrated in FIG. 12. Although FIG. 12 illustrates the example inwhich the smartphone 900 includes multiple antennas 916, the smartphone900 may also include a single antenna 916.

Furthermore, the smartphone 900 may include the antenna 916 for eachradio communication scheme. In that case, the antenna switches 915 maybe omitted from the configuration of the smartphone 900.

The bus 917 connects the processor 901, the memory 902, the storage 903,the external connection interface 904, the camera 906, the sensor 907,the microphone 908, the input device 909, the display device 910, thespeaker 911, the radio communication interface 912, and the auxiliarycontroller 919 to each other. The battery 918 supplies power to blocksof the smartphone 900 illustrated in FIG. 12 via feeder lines, which arepartially shown as dashed lines in the figure. The auxiliary controller919 operates a minimum necessary function of the smartphone 900, forexample, in a sleep mode.

In the smartphone 900 illustrated in FIG. 12, one or more of thecomponents comprised in the processing circuitry 201 (the reporting unit202, the determining unit 203, the notifying unit 204) described withreference to FIG. 2A or one or more of the components comprised in theprocessing circuitry 701 (the reporting unit 702, the notificationreceiving unit 703) described with reference to FIG. 7A may beimplemented in the radio communication interface 912. Alternatively, atleast a part of these components may also be implemented in theprocessor 901 or the auxiliary controller 919. As an example, thesmartphone 900 include a part (for example, the BB processor 913) or theentire of the radio communication interface 912, and/or a moduleincluding the processor 901 and/or the auxiliary controller 919, and theone or more components may be implemented in the module. In this case,the module may store a program (in other words, a program causing theprocessor to execute operations of the one or more components) causingthe processor to function as the one or more components, and execute theprogram. As another example, a program causing the processor to functionas the one or more components may be installed in the smartphone 900,and the radio communication interface 912 (for example, the BB processor913), the processor 901 and/or the auxiliary controller 919 may executethe program. As described above, as a device including the one or morecomponents, the smartphone 900 or the module may be provided. A programcausing the processor to function as the one or more components may alsobe provided. In addition, a readable medium in which the program isrecorded may be provided.

In addition, in the smartphone 900 illustrated in FIG. 12, for example,the communication unit 205 described with reference to FIG. 2A or thecommunication unit 705 described with reference to FIG. 7A may beimplemented in the radio communication interface 912, for example, theRF circuit 914.

Second Application Example

FIG. 13 is a block diagram illustrating an example of a schematicconfiguration of a car navigation device 920 to which an embodiment ofthe technology of the present application may be applied. Wherein thecar navigation device 920 can be implemented as the electronic device200 described with reference to FIG. 2A or the electronic device 700described with reference to FIG. 7A. The car navigation device 920includes a processor 921, a memory 922, a global positioning system(GPS) module 924, a sensor 925, a data interface 926, a content player927, a storage medium interface 928, an input device 929, a displaydevice 930, a speaker 931, a radio communication interface 933, one ormore antenna switches 936, one or more antennas 937, and a battery 938.

The processor 921 may be, for example, a CPU or a SoC, and controls anavigation function and other functions of the car navigation device920. The memory 922 includes RAM and ROM, and stores a program that isexecuted by the processor 921, and data.

The GPS module 924 uses GPS signals received from a GPS satellite tomeasure a position, such as latitude, longitude, and altitude, of thecar navigation device 920. The sensor 925 may include a group of sensorssuch as a gyro sensor, a geomagnetic sensor, and an air pressure sensor.The data interface 926 is connected to, for example, an in-vehiclenetwork 941 via a terminal that is not shown, and acquires datagenerated by the vehicle, such as vehicle speed data.

The content player 927 reproduces content stored in a storage medium,such as a CD and a DVD, that is inserted into the storage mediuminterface 928. The input device 929 includes, for example, a touchsensor configured to detect touch onto a screen of the display device930, a button, or a switch, and receives an operation or an informationinput from a user. The display device 930 includes a screen such as aLCD or an OLED display, and displays an image of the navigation functionor content that is reproduced. The speaker 931 outputs sounds of thenavigation function or the content that is reproduced.

The radio communication interface 933 supports any cellularcommunication scheme, such as LET and LTE-Advanced, and performs radiocommunication. The radio communication interface 933 may typicallyinclude, for example, a BB processor 934 and an RF circuit 935. The BBprocessor 934 may perform, for example, encoding/decoding,modulating/demodulating, and multiplexing/demultiplexing, and performsvarious types of signal processing for radio communication. Meanwhile,the RF circuit 935 may include, for example, a mixer, a filter, and anamplifier, and transmits and receives radio signals via the antenna 937.The radio communication interface 933 may be a one chip module whichintegrates the BB processor 934 and the RF circuit 935 thereon. Theradio communication interface 933 may induce multiple BB processors 934and multiple RF circuits 935, as illustrated in FIG. 13. Although FIG.13 illustrates the example in which the radio communication interface933 includes multiple BB processors 934 and multiple RF circuits 935,the radio communication interface 933 may also include a single BBprocessor 934 or a single RF circuit 935.

Furthermore, in addition to a cellular communication scheme, the radiocommunication interface 933 may support another type of radiocommunication scheme such as a short-distance wireless communicationscheme, a near field communication scheme, and a wireless LAN scheme. Inthat case, the radio communication interface 933 may include the BBprocessor 934 and the RF circuit 935 for each radio communicationscheme.

Each of the antenna switches 936 switches connection destinations of theantennas 937 among multiple circuits (such as circuits for differentradio communication schemes) included in the radio communicationinterface 933.

Each of the antennas 937 includes a single or multiple antenna elements,such as multiple antenna elements included in an MIMO antenna, and isused for the radio communication interface 933 to transmit and receiveradio signals. The car navigation device 920 may include the multipleantennas 937, as illustrated in FIG. 13. Although FIG. 13 illustratesthe example in which the car navigation device 920 includes multipleantennas 937, the car navigation device 920 may also include a singleantenna 937.

Furthermore, the car navigation device 920 may include the antenna 937for each radio communication scheme. In that case, the antenna switches936 may be omitted from the configuration of the car navigation device920.

The battery 938 supplies power to blocks of the car navigation device920 illustrated in FIG. 13 via feeder lines that are partially shown asdashed lines in the figure. The battery 938 accumulates power suppliedfrom the vehicle.

In the car navigation device 920 illustrated in FIG. 13, one or more ofthe components comprised in the processing circuitry 201 (the reportingunit 202, the determining unit 203, the notifying unit 204) describedwith reference to FIG. 2A or one or more of the components comprised inthe processing circuitry 701 (the reporting unit 702, the notificationreceiving unit 703) described with reference to FIG. 7A may beimplemented in the radio communication interface 933. Alternatively, atleast a part of these components may also be implemented in theprocessor 921. As an example, the car navigation device 920 includes apart (for example, the BB processor 934) or the entire of the radiocommunication interface 933 and/or a module including the processor 921,and the one or more components may be implemented in the module. In thiscase, the module may store a program (in other words, a program causingthe processor to execute operations of the one or more components)causing the processor to function as the one or mere components, andexecute the program. As another example, a program causing the processorto function as the one or more components may be installed in the carnavigation device 920, and the radio communication interface 933 (forexample, the BB processor 934) and/or the processor 921 may execute theprogram. As described above, as a device including the one or morecomponents, the car navigation device 920 or the module may be provided.A program causing the processor to function as the one or morecomponents may also be provided. In addition, a readable medium in whichthe program is recorded may be provided.

In addition, in the car navigation device 920 illustrated in FIG. 13,for example, the communication unit 205 described with reference to FIG.2A or the communication unit 705 described with reference to FIG. 7A maybe implemented in the radio communication interface 933, for example,the RF circuit 935.

Technology of the present application may also be realized as anin-vehicle system (or a vehicle) 940 including one or more blocks of thecar navigation device 920, the in-vehicle network 941, and a vehiclemodule 942. The vehicle module 942 generates vehicle data such asvehicle speed, engine speed, and trouble information, and outputs thegenerated data to the in-vehicle network 941.

In addition, a readable storage medium recoding a program therein can beprovided. Therefore, the present disclosure also relates to a computerreadable storage medium storing a program including instructionsthereon, which, when loaded into and executed by the processingcircuitry, are used to perform the communication methods as described inFIGS. 2B, 3B, 6B and 7B.

Although the illustrative embodiments of the present disclosure havebeen described with reference to the accompanying drawings, the presentdisclosure is certainly not limited to the above examples. Those skilledin the art can achieve various adaptions and modifications within thescope of the appended claims, and it will be appreciated that theseadaptions and modifications certainly fall into the scope of thetechnology of the present disclosure.

For example, in the above embodiments, the multiple functions includedin one module can be implemented by separate means. Alternatively, inthe above embodiments, the multiple functions included in multiplemodules can be implemented by separate means, respectively. Inadditions, one of the above functions can be implemented by multiplemodules. Needless to say, such configurations are included in the scopeof the technology or the present disclosure.

In this specification, the steps described in the flowcharts include notonly the processes performed sequentially in chronological order, butalso the processes performed in parallel or separately but notnecessarily performed in chronological order. Furthermore, even in thesteps performed in chronological order, needless to say, the order canbe changed appropriately.

Although the present disclosure and its advantages have been describedin detail, it will be appreciated that various changes, replacements andtransformations can be made without departing from the spirit and scopeof the present disclosure as defined by the appended claims. Inaddition, the terms “include”, “comprise” or any other variants of theembodiments of the present disclosure are intended to be non-exclusiveinclusion, such that the process, method, article or device including aseries of elements includes not only these elements, but also those thatare not listed specifically, or those that are inherent to the process,method, article or device. In case of further limitations, the elementdefined by the sentence “include one” does not exclude the presence ofadditional same elements in the process, method, article or deviceincluding this element.

What is claimed is:
 1. An electronic device in a wireless communicationsystem comprising a processing circuitry configured to report, to anetwork control device, a first type of channel state information (CSI)by using a resource for a first type of channel state feedback allocatedby the network control device; make a determination that a second typeof channel state feedback is required, the determination being madebased on an orthogonality between a communication resource used by theelectronic device and a communication resource used by anotherelectronic device; and notify the network control device of thedetermination.
 2. An electronic device in a wireless communicationsystem comprising a processing circuitry configured to allocate aresource for a first type of channel state feedback to a user device;make a determination that a second type of channel state feedback isrequired, the determination being made based on an orthogonality betweena communication resource used by the user device and a communicationresource used by another user device; and notify the user device of thedetermination.
 3. The electronic device according to claim 1, whereinthe orthogonality is decided based on a scrambling code sequence ofdemodulation reference signal (DMRS) port used by the electronic deviceand a scrambling code sequence of DMRS port used by the anotherelectronic device.
 4. The electronic device according to claim 3,wherein the electronic device requests the network control device forinformation on the scrambling code sequence of DMRS port used by theanother electronic device.
 5. The electronic device according to claim1, wherein the determination is made based on a degradation degree ofchannel quality of a channel between the electronic device and thenetwork control device.
 6. The electronic device according to claim 5,wherein the degradation degree is indicated by a difference between thechannel quality in a single-user communication and the channel qualityin a multi-user communication of the electronic device and the networkcontrol device.
 7. The electronic device according to claim 1, whereinthe notifying is implemented with information indicating category of thesecond type of channel state feedback.
 8. The electronic deviceaccording to claim 7, wherein the information indicating category of thesecond type of channel state feedback is contained in uplink controlinformation (UCI).
 9. The electronic device according to claim 1,wherein the processing circuitry is further configured to report, to thenetwork control device, a second type of CSI by using a resource for thesecond type of channel state feedback allocated by the network controldevice.
 10. The electronic device according to claim 2, wherein theprocessing circuitry is further configured to allocate a resource forthe second type of channel state feedback to the electronic device so asto allow the electronic device to report a second type of CSI.
 11. Theelectronic device according to claim 1, wherein a communication betweenthe electronic device and the network control device is a part ofmulti-user multi-input multi-output (MU-MIMO) communication.
 12. Theelectronic device according to claim 1, wherein the second type ofchannel state feedback includes any of pre-coding feedback based onlinearly combined codebook, feedback based on covariance matrix, andhybrid CSI feedback.
 13. An electronic device in a wirelesscommunication system comprising a processing circuitry configured toallocate a resource for a first type of channel state feedback to a userdevice; receive, from the user device, a notification regarding adetermination that a second type of channel state feedback is required,the determination being made based on an orthogonality between acommunication resource used by the user device and a communicationresource used by another user device; allocate a resource for the secondtype of channel state feedback to the user device; and receive a secondtype of channel state information (CSI).
 14. An electronic device in awireless communication system comprising a processing circuitryconfigured to report, to a network control device, a first type ofchannel state information (CSI) by using a resource for a first type ofchannel state feedback allocated by the network control device; receive,from the network control device, a notification regarding adetermination that a second type of channel state feedback is required,the determination being made based on an orthogonality between acommunication resource used by the electronic device and a communicationresource used by another electronic device; and report, to the networkcontrol device, a second type of CSI by using a resource for the secondtype of channel state feedback allocated by the network control device.15. The electronic device according to claim 13, wherein theorthogonality is decided based on a scrambling code sequence ofdemodulation reference signal (DMRS) port used by the user device and ascrambling code sequence of DMRS port used by the another user device.16. The electronic device according to claim 1, wherein thedetermination is made based on a degradation degree of channel qualityof a channel between the electronic device and the network controldevice.
 17. The electronic device according to claim 1, wherein thenotification is implemented with information indicating category of thesecond type of channel state feedback.
 18. The electronic deviceaccording to claim 1, wherein the communication between the electronicdevice and the network control device is a part of multi-usermulti-input multi-output (MU-MIMO) communication.
 19. The electronicdevice according to claim 1, wherein the second type of channel statefeedback includes any of pre-coding feedback based on linearly combinedcodebook, feedback based on covariance matrix, and hybrid CST feedback.